The present invention was devised for producing parts of a sprayer of a type that is fastened to the end of a garden hose to aspirate a treating solution from a container and mix the solution with the water from the garden hose. The aspiration takes place by means of a Venturi in the sprayer.
Such sprayers are designed so as to mix predetermined proportions of the aspirated liquid with the water flowing through the garden hose. Thus, the user of the sprayer will know the dosage of weed killer, pesticide, etc., that is being applied through the use of the sprayer. The specific proportions are achieved by the configuration of the Venturi; that is, with a Venturi of one design the proportions may be 1 in 100, while with another design that may be 5 or 10 in 100, etc. To achieve the desired proportions requires substantial accuracy in the manufacture of the Venturi.
One of the past practices for Venturi manufacture has been to define a step in the Venturi tube by two concentric openings of different diameters, the step being at the plane where the two openings meet. Merely drilling two such openings through a body part did not produce sufficient accuracy to consistently produce Venturies having the desired mixing proportion. It has been necessary to ream at least one of the openings, and often both, to achieve sufficient accuracy in the opening sizes. Even so, the process of reaming required considerable skill and experience to consistently come up with parts having the desired mixing capabilities. It was, you might say, an "art" to produce such parts.
This method of manufacture was inherently expensive. Such expense was particularly undesirable because the overall sprayers are a relatively inexpensive item; that is, purchasers would not buy the item at a particularly greater price. They would use some alternative method of achieving the same result rather than buy the more expensive sprayer.
The principal object of the present invention is to provide an alternative procedure for making the Venturi in such sprayer nozzles. Not only does the present invention achieve a substantial reduction in cost of manufacture, but the manufacturing procedure is not an "art" and may be performed by a relatively inexperienced worker while still achieving the required accuracy in the operation of the finished sprayer. As a matter of fact, if tests should show that the parts being produced were outside the range desired, it is a very simple matter to correct the manufacturing operation to bring the product back within the required tolerance range.
Further objects and advantages will be apparent from the following.